Conventional shotguns suffer from a number of problems in a variety of areas. The problems may be manifest in the operation and reliability of the action, ease of disassembly for cleaning or other purposes, ability to load and/or unload the firearm, and the like. These problems may be especially applicable to autoloading shotguns having semi-automatic or fully-automatic actions. The following provides some background about some of the problems associated with shotguns.
Most shotguns are designed to bias or retract the firing pin rearward when the bolt is unlocked. This is done for a number of reasons. For one, it is undesirable to have the firing pin protruding forward out of the face of the bolt during the process of chambering a new shotshell (also referred to as a shotgun shell or shotgun cartridge). The rim of the shotshell may catch on the firing pin and jam the action.
Over the years, a number of different designs have been developed to bias or retract the firing pin rearward when the bolt is unlocked. For example, one design uses a rotary bolt that has a slot that guides rearward movement of the firing pin. As the bolt rotates from a locked position to an unlocked position, the shape of the slot forces the firing pin rearward and holds it in place until the bolt rotates back to lock with the barrel. In other designs, a spring may be used to bias the firing pin rearward. The spring is provided with sufficient stiffness to prevent the firing pin from moving forward during routine cycling of the action, but still allow the hammer to push the firing pin forward when the bolt is locked in place and the shotgun is ready to fire. Still other designs may use a bolt assembly that is formed of a large number of pieces that move in concert to restrain the firing pin as well as perform all of the other functions of the bolt assembly when the action cycles.
Unfortunately, existing designs for locking the firing pin suffer from a number of disadvantages. For example, rotary bolt designs require a longer receiver, which increases the overall length and weight of the shotgun. Also, rotary bolt designs are relatively complex in operation, which makes them more susceptible to reliability problems. Spring biased firing pins work well initially but may fail with heavy usage (e.g., 6,000 to 10,000 cycles of the action). The typical failure point is the spring which breaks, loses its spring, or is otherwise rendered unusable—often at the most inopportune time such as during a hunt. Bolt assemblies that use large numbers of pieces are also quite complex, which renders them more susceptible to problems. They are also regarded as being weaker than other designs. Accordingly, it would be desirable to provide an improved shotgun that locks the firing pin and uses a relatively simple and strong bolt assembly.
Another problem area associated with conventional shotguns is the mechanism used to couple the forearm to the remainder of the shotgun. Conventional shotguns use a cap that screws on to the end of the magazine tube to hold the forearm to the remainder of the shotgun. In order to remove the forearm, the cap must be completely removed through repeated twisting. Once removed, the cap may be easily lost, especially if the cap is removed in the field, e.g. in a boat while hunting waterfowl, in tall grass while hunting upland birds, etc.
It can be especially difficult to remove the forearm from a conventional shotgun that has a sling. Most conventional shotguns include a sling mount as part of the cap that holds the forearm to the remainder of the shot. The sling mount provides a hole that is sized to receive a conventional sling swivel that is, in turn, coupled to the sling. The presence of the sling makes it more difficult to rotate and remove the cap. Although it is possible to remove the cap with the sling attached, many users find it easier to detach the sling swivel then remove the cap. Accordingly, it would be desirable to provide a fastening mechanism that is easy and simple to use and is an improvement over conventional designs.
Another problem area for conventional shotguns is associated with the use of magazine plugs or magazine capacity reducers. A magazine plug is a device that is placed in the magazine of a shotgun to limit the number of shotshells that the shotgun can hold at one time. The magazine plug is used to comply with laws that restrict the maximum number of shotshells a shotgun can hold when the user is hunting certain species of game, such as waterfowl. Most of these laws allow a maximum of three shotshells to be in the shotgun (e.g., one in the chamber and two in the magazine).
The law also requires that the shotgun must be disassembled to some degree to place the plug into the magazine of the shotgun. In order to comply, most shotguns are designed to require the user to remove at least the magazine cap in order to insert the plug into the magazine. If it is too easy to change the capacity of the magazine, the user could hunt with the shotgun in a high capacity setting until he sees the warden at which time he could quickly change to the low capacity setting.
One problem with conventional shotguns is that when the user removes the magazine cap to insert the plug, the spring inside the magazine, which is under compression, tends to shoot out. If the user is not careful, it is possible for the spring to come completely out of the magazine and become lost or dirty. Another problem is that even if the spring doesn't shoot out, the spring retainer assembly—a small device positioned between the spring and the cap—may shoot out or fall off and become lost or dirty.
Even if the cap is successfully removed without losing any parts, the user must still fight the spring to get the plug into the magazine. In order to insert the plug, the user must compress the spring into the magazine, put the plug into position, and hold everything in place while simultaneously putting the cap back on the magazine. Any false moves and the plug, spring, and/or spring retainer assembly may shoot out of the magazine. Accordingly, it would be desirable to provide an improved shotgun and/or magazine plug that allows the magazine plug to be inserted into the magazine in an easier fashion while still complying with applicable laws that require disassembly of the shotgun.
Another problem area associated with convention shotguns is the shotshell feeding mechanism. The feeding mechanism is part of the action and is used to feed shotshells from the magazine to the chamber of the shotgun. One problem with conventional feeding mechanisms arises when the user desires to unload the magazine. In many conventional shotguns, the user must cycle the shotshell through the action and eject the shotshell through an ejection port. Another problem arises when the user wants to quickly load the shotgun. Most conventional shotguns require the user to insert a shotshell into the magazine and push a button to close the action (if it is open) or otherwise operate the action to load the shotshell into the chamber. These additional steps eat up time that may make the difference between bagging game or hitting the desired target and going home empty handed or missing the target.
There are some shotguns that may have a solution for one of these problems alone. However, it would be desirable to provide a shotgun that allows the user the ability to quickly load the chamber without any manual input beyond inserting the shotshell into the magazine and to easily unload the magazine without cycling and ejecting the shotshell through the ejection port.
Another problem area for conventional shotguns is associated with the use of gas-operated actions. A gas-operated shotgun is a shotgun that uses a portion of the high pressure gas generated when the shotshell is fired to power a mechanism to extract the spent shotshell and chamber a new shotshell. Energy from the gas is typically harnessed through a port in the barrel. The high-pressure gas enters a cylinder that contains a piston. The pressure in the cylinder causes the piston to move which provides motion to unlock the action, extract and eject the spent shotshell, cock the hammer, chamber a new shotshell, and lock the action. In most gas-operated shotguns, the piston is forced rearward and the force from the rearward motion of the piston is transferred to the bolt assembly thereby unlocking and opening the action and initiating the process of ejecting the spent shotshell and chambering a new shotshell. A gas-operated shotgun functions in much the same way as a gas-operated rifle. However, unlike most rifles, the piston in a shotgun surrounds the magazine.
Conventional gas-operated shotguns suffer from a number of problems. Some shotguns use O-rings to form a seal around the piston. However, this configuration is unreliable due to the constant movement of steel and O-ring against each other. Over time, excessive wear on either the rubber O-ring or the steel allows the gas to leak out of the cylinder. Eventually, so much gas leaks out of the cylinder that the force generated by the piston is insufficient to extract the spent shotshell and chamber a new one. Repairing the shotgun typically requires replacing or rebuilding the worn parts, a task that can be time consuming and/or expensive.
In an effort to reduce the wear, metal rings have been used in place of O-rings. The metal rings have been fitted between the piston and the magazine tube of the shotgun. The metal rings are engineered to tight tolerances to prevent gas from leaking past the rings. Although the rings successfully reduce the amount of wear, they have been less successful in preventing gas from leaking out of the cylinder. The combustion gas contains carbon, soot, and other solid combustion products. The leaking gas causes these materials to build-up on the shotgun's magazine as well as on other components. This contributes to the negative perception of gas-operated shotguns as being dirty and requiring frequent cleaning. Accordingly, it would be desirable to develop a seal that reduces wear associated with movement of the piston and still maintains a good seal to prevent gas from leaking out of the cylinder.